1. Field of the Invention
The present invention relates to a safety assembly structure of a curtain bead chain to prevent children's neck from being wrapped around by the bead chain.
2. Description of Related Art
Generally, retractor structures on existing curtains are equipped with a flexible pulling cord for users to control the curtain, allowing the curtain to vertically or horizontally shrink or extend. The conventional curtain structure is provided with a rotating axis with a curtain wrapped up thereon, and a retractor having a bead chain is disposed on the rotating axis. The retractor and the rotating axis can be driven to control the curtain by pulling the bead chain. However, bead chains are ring-shaped and have a relative high toughness, unsophisticated children who are curious about bead chains and playing them would sometimes have choking accidents due to their necks being wrapped around by bead chains. To avoid the accident, a Taiwan Patent No. M400279, issued on 21 Mar. 2011, has disclosed a safety connecting assembly of a curtain pulling cord, comprising a first connecting block and a second connecting block, wherein the first connecting block includes a main body for fixing on a predetermined end of the curtain pulling cord, the main body has a connecting surface having a convex pillar provided with a convex body thereon, the second connecting block includes a main body for fixing on a predetermined end of the curtain pulling cord, the main body has a connecting surface having an engaging slot for engaging the convex pillar therein, and the engaging slot is provided with a fixing recess on the internal wall for engaging the convex body. Accordingly, if the curtain pulling cord receives a pulling force exceeding a predetermined value, the first connecting block and the second connecting block are allowed to disconnect. However, aforementioned structures have the following disadvantages in production and use thereof:
1. The structure is only suitable for a pulling cord having a large diameter, such as 8 mm.
2. It is difficult to manufacture the pulling cord having a diameter less than 4.5 mm in a mold and even difficult to model the same.
3. Plastic injection molding in a small space may cause a volume change due to cold shrinkage, resulting in an increased defective rate.
4. The second connecting piece having a diameter of 4.5 mm cannot adequately wrap up the string so that the string is prone to detach from the connecting piece and cannot bear too much tension in a case of using large curtains.